Microbial attachment to mineral surfaces Extracellular polysaccharides and other complex polymeric structures are synthesized by bacteria during the second or irreversible stage of adsorption to surfaces. These extracellular polysaccharides are highly hydrated structures consisting of greater than 99% water. As such, they are extremely difficult to prepare for electron microscopy examination. The use of high pressure cryofixation, freeze-etch/drying and metal coating, followed by high resolution scanning electron microscopy should obviate such artifacts as solute migration and allow a better understanding of the extent and ultrastructure of these biological structures.